The present invention relates generally to hair dryers, and more particularly, to portable combination hair moisturizers and dryers. It relates to an improvement in those hair dryers having rigid dryer head assemblies which include portions adapted to surround at least a part of the head of the user and which are occasionally referred to in the trade as "hard hat" hair dryers. A preferred embodiment of the present invention relates generally to hair dryers of the type having the configuration of an articulated, nestable "Z".
Such hard hat dryers are readily distinguishable from other types of dryers such as dryers having flexible bags or caps which surround the head of the user and which include a flexible hose-like conduit extending between the cap and a blower for heated air, and from dryers of the hand-held type, wherein no means are provided for surrounding any substantial portion of the head of the user. Although hair dryers of both the hand-held type and flexible cap type are proven acceptable to the trade, it is well known that hair dryers having the rigid drying head or hood units are superior in use, principally because they are sufficiently rigid to contain a fixed physical structure which serves to direct the air to desired portions of the hair of the user in accordance with a pre-determined pattern. Recently, hair dryers of the rigid hat or hard hat type have become relatively common home appliances, and have certain currency because they have been able to be manufactured at reasonable prices. Such dryers are generally designed so as to overcome the drawbacks associated with commercial or heavy-duty hair dryers, namely, substantial mass, lack of portability, and the requirement of using substantial amounts of electrical current.
The most preferred embodiment of the present invention can be regarded as an improvement over dryers which are disclosed in co-pending U.S. Pat. application Ser. No. 229,763, filed Feb. 28, 1972 by Robert S. Waters, Edward J. Doyle, Meryic K. Rogers, and Nial C. Bartram ans assigned to a common assignee with the present invention. The hard-hat dryer disclosed in that patent application provides a head assembly and a base, each of which are respectively pivotally mounted at opposite ends of the head mounting assembly on parallel horizontal axes in such a manner that the head and the base assembly can be pivoted with respect to the head assembly to nest the base and head mounting assembly within the head assembly, or it can be opened into the general configuration of a Z without requiring dismantling or separation and reassembly of the dryer.
In the dryers described in the aforementioned patent application, the head assembly included an upper shell disposed above and about a generally annular plenum, and this shell is pivotally mounted on a separate horizontal axis to expand the volume generally enclosed by the annular plenum and shell assembly.
As indicated above, hard hat hair dryers have proven acceptable and are eminently satisfactory for use as hair dryers. One of the advantages of the hard hat hair dryers of the type described and claimed in the aforementioned patent application is the fact that these hair dryers readily lend themselves for eminently satisfactory use by a user having a number of relatively large curlers in her hair at the time of use.
While it is not the purpose of the present discussion to elaborate in great detail on all the factors relating to the "setting" of curls in hair, or relating to the effects of moisture on the curling and setting of hair, it has been accepted by the industry and by the consumer public that the best and longest-lasting hair set is obtained by washing the hair, putting it up in curlers wet, and drying it with a hard or soft bonnet type hair dryer. This method introduces the maximum amount of moisture into the hair itself, imparting the maximum set and the longest-lasting curl retention. Utilization of the same step sequence on dry hair produces little or no result.
An alternative method of setting hair which does not involve the washing step as a preliminary, is to provide the same step sequence with dry hair, using rollers with moisture available on the rollers to provide a quick set on drying. This method gives a lasting set of acceptable duration and is one of the quickest and most convenient to do. However, tests have shown that another alternative hair setting procedure which imparts a lasting set which is second in duration only to that achieved by the first procedure involving washing hair, putting it up in curlers wet, and drying it in a hair dryer, is that alternative method in which dry hair is rolled on curlers, moisturized by moisture-laden air mist mixture and then subjected to drying.
While it is not intended that the present invention be bound by, or limited to, any particular chemical theories, at least the following brief explanation of the presently accepted understanding of some of the physical-chemical factors involved in the hair setting phenomenon is deemed to be desirable. Some present authorities regard hair fiber as being made of molecular chains of atoms which are folded upon themselves much like accordian pleats. These authorities believe that some hydrogen bonding occurs between the molecules, and between different portions of the same molecules, and that this bonding is responsible for the characteristic known as hair setting. It is well known that water softens hair and in some instances to such an extent that it can be stretched when totally wet up to several times its initial length without breaking. Furthermore, there is no critical point of full wetness which must be attained before the hair can be so influenced. The ability of hair to be stretched is reported to increase in proportion to the amount of water it has absorbed, either from liquid water, or from water vapor present in the air.
Wetting or hydration of the hydrogen bonds referred to above releases the normal hydrogen bonding attachments within the hair fiber. As a result, moisturization will relax the hair molecular structure by causing the hydrogen bonds to release their hold, allowing the pleats to unfold and the molecules to change position and to bypass each other. One might visualize the hair as a resilient system of fibrous molecules packed together much like the fibers of a strand of hemp rope. Under ambient conditions this system comprises a natural inter-molecular hydrogen bonding mixture of attached hydrogen bonds in equilibrium with some that are not attached. The ratio of the attached to unattached bonds also depends in part on the number of available water molecules within the system. The greater the number of attached bonds (as in dry hair) the harder and stiffer is the system. As more of these hydrogen bonds become unattached (as in moisturized, wetter hair) the system becomes more flexible and more easily stretched.
If hair is bent as when curling, compression stresses develop on the inside of the curve while tension stresses develop on the outside elongated portion of the hair. If hydration moisture is available at the hydrogen bonds resisting these internal stresses these bonds tend to lose their original attachment. The molecular "pleats" in the hair under tension can relax and can be pulled open as a consequence. At the same time some molecules slide slightly along others. Both of these effects occur to reduce the tension stresses developed by bending the hair. In a similar way, the compression stress is also relieved and reduced.
If the hair is now held bent until dry, new hydrogen bonds reform automatically, but at new locations, such as to hold the hair in bent position. Pleats are now held open, or more tightly closed, depending on their configuration at that particular portion of the hair strand when the hair is physically held in the desired curled configuration. Molecules that have shifted in position along others are now also held in their new location. The end result is a new curled configuration of the original hair with little or no molecular "memory" which would tend to cause the hair to return to its pre-setting configuration.
Thus, these physical-chemical explanations by the authorities assist in understanding why wet hair will produce the tightest or longest-lasting curls when dried on suitable curlers. Under these conditions, the greatest number of hydrogen bonds are affected, that is, released and then reformed. However, if hair is not totally wet, then some of the hydrogen bonds are not affected in the curling process, which leads them to strain against those which were effected. This is part of the basis for the molecular memory referred to above which generates internal forces which tend to return the hair to its original pre-curl configuration. Such a situation produces looser or shorter-lasting curls. The more moisture applied at the inception of the curling process, the more effective it is believed that it will be. Hot dry curlers can curl hair under certain conditions, but the curls resulting will depend on the amount of moisture already in the hair at the start of the procedure. Such curls appear because of the drying out of the moisture produced new hydrogen bonds in configuration to hold the curl. However, these bonds will be constantly straining against bonds that were not previously broken, and against compressive or stretching forces that were not previously relieved, and, thus, the curls formed by the hot-dry curlers will not remain as permanently. If moisture is added as in the hot wet curlers, or by means of a moisture-laden airmist mixture, then more hydrogen bonding of the old configuration is released, relieving the internal molecular memory forces. Then, during re-drying, new hydrogen bonding occurs to provide a lasting set to the hair in the new curled configuration.
Thus, when some provision is made to moisturize the hair while it is physically maintained in curled condition, the hair need not be so completely dried out in order to make a substantially longer-lasting curl.
It is generally regarded as undesirable to dry the hair too much, because the dryer the hair, the harder and less flexible it becomes, for the reasons outlined above. If hair can be curled adequately without the need to drive moisture out to a "too dry" level, the resulting curl will be softer, and the hair in the curls will be more resilient and less liable to fracture during the final combing and arranging of the curls. In the final arranging and combing, the hair receives the most severe mechanical abuse. If the hair is too dry at this time, it is more likely to fracture and produce split ends and broken hair shafts. If sufficient moisture is retained in the curl during this stage, it is less brittle and more able to withstand mechanical abuse. It will be appreciated, however, that whatever the true physical-chemical explanations or reasons for the eminently satisfactory results of the operation of the present invention, it is effective, and hence, the present disclosure is not dependent upon any particular theory or explanation as to the physical-chemical phenomenon within the hair itself.
It is an important feature of the present invention to provide a portable means for effectively moisturizing hair while in curlers in conjunction with a portable hard-hat hair dryer.
It is another object of the present invention to provide a hair moisturizer and dryer having a configuration in which a head assembly thereof will occupy the necessary but minimal volume when the hair moisturizer and dryer is in a stored configuration, and yet in which the head assembly can be expanded automatically to provide adequate volume for use by a person having a plurality of relatively large curlers, for example, which combination moisturizer and dryer also provides means for uniformly imparting stress-relieving moisture to the hair.
It is a further object of the present invention to provide a portable combination hair moisturizer and dryer having an easily stored hinged Z configuration, having means for generating and for providing uniform distribution of moisture vapor and mist to the hair, which generating means are supported in the central head-supporting element of the hinged Z and which moisturizer and dryer has a water reservoir configuration such that normal residual amounts of water will tend not to be spilled therefrom when the hinged Z hair moisturizer and dryer is converted to its storage configuration.
It is a further object of the present invention to provide a portable hinged Z hard hat moisturizer and dryer which includes means for providing penetrating water-moisture to all hair surfaces, which means is mounted for long-lasting substantially trouble-free use, and which can be efficiently and economically assembled during manufacture.
It is a further object of the present invention to provide a hair mister-dryer which has the operating configuration of a Z and in which steam generating means are carried in the intermediate head-supporting element.
It is another object of the present invention to provide a hard-hat hair dryer with moisturization means, and also having air impelling and heating means, wherein the blowing and heating means are not subjected to corrosive effects of the generated steam.
It is a further object of the present invention to provide a hard-hat hair steamer and dryer in which hair internal stress is relieved by moisture, wherein the moisture is provided in the form of a concentrated mixture of vaporized water, in air, which mixture also contains a fine mist of extremely tiny droplets, if desired.